fixup wml menu items: track the lifetime of the manager

testing revealed that assertions may fail regarding the lifetime
of the manager of wml menu items in some cases. this commit adds
a pointer to each which tracks its manager's life time and prevents
dangling pointers.

src/game_events/manager.cpp

@@ -32,6 +32,8 @@
 #include "util.hpp"
 
 #include <boost/foreach.hpp>
+#include <boost/make_shared.hpp>
+#include <boost/shared_ptr.hpp>
 #include <boost/unordered_map.hpp>
 #include <iostream>
 
@@ -99,6 +101,7 @@ manager::manager(const config& cfg, const boost::shared_ptr<t_context> & res)
 	, used_items_()
 	, pump_(new game_events::t_pump(*this, res))
 	, resources_(res)
+	, me_(boost::make_shared<manager * const>(this))
 {
 	BOOST_FOREACH(const config &ev, cfg.child_range("event")) {
 		add_event_handler(ev);
@@ -126,7 +129,7 @@ manager::manager(const config& cfg, const boost::shared_ptr<t_context> & res)
 	}
 
 	// Create the event handlers for menu items.
-	resources_->gamedata->get_wml_menu_items().init_handlers();
+	resources_->gamedata->get_wml_menu_items().init_handlers(me_);
 }
 
 manager::~manager() {}

src/game_events/manager.hpp

@@ -115,6 +115,7 @@ namespace game_events {
 
 		boost::scoped_ptr<game_events::t_pump> pump_;
 		boost::shared_ptr<t_context> resources_;
+		boost::shared_ptr<manager* const> me_;
 
 	public:
 		/// Note that references will be maintained,

src/game_events/menu_item.cpp

@@ -37,7 +37,6 @@
 #include "../preferences.hpp"
 #include "../replay.hpp"
 #include "../replay_helper.hpp"
-#include "../resources.hpp"
 #include "../synced_context.hpp"
 #include "../terrain_filter.hpp"
 
@@ -92,7 +91,8 @@ wml_menu_item::wml_menu_item(const std::string& id, const config & cfg) :
 		command_(cfg.child_or_empty("command")),
 		default_hotkey_(cfg.child_or_empty("default_hotkey")),
 		use_hotkey_(cfg["use_hotkey"].to_bool(true)),
-		use_wml_menu_(cfg["use_hotkey"].str() != "only")
+		use_wml_menu_(cfg["use_hotkey"].str() != "only"),
+		my_manager_()
 {
 }
 
@@ -146,7 +146,8 @@ wml_menu_item::wml_menu_item(const std::string& id, const vconfig & definition,
 		command_(original.command_),
 		default_hotkey_(original.default_hotkey_),
 		use_hotkey_(original.use_hotkey_),
-		use_wml_menu_(original.use_wml_menu_)
+		use_wml_menu_(original.use_wml_menu_),
+		my_manager_()
 {
 	// Apply WML.
 	update(definition);
@@ -221,24 +222,29 @@ void wml_menu_item::fire_event(const map_location & event_hex, const game_data &
 void wml_menu_item::finish_handler() const
 {
 	if ( !command_.empty() ) {
-		assert(resources::game_events);
-		resources::game_events->remove_event_handler(command_["id"]);
+		if (boost::shared_ptr<manager * const> man = my_manager_.lock()) {
+			(**man).remove_event_handler(command_["id"]);
+		} else {
+			LOG_NG << "Tried to finish handler for a wml menu item, but the manager could not be found.\n";
+		}
 	}
 
 	// Hotkey support
-	if ( use_hotkey_ )
+	if ( use_hotkey_ ) {
 		hotkey::remove_wml_hotkey(hotkey_id_);
+	}
 }
 
 /**
  * Initializes the implicit event handler for an inlined [command].
  */
-void wml_menu_item::init_handler() const
+void wml_menu_item::init_handler(const boost::shared_ptr<manager * const> & man) const
 {
 	// If this menu item has a [command], add a handler for it.
 	if ( !command_.empty() ) {
-		assert(resources::game_events);
-		resources::game_events->add_event_handler(command_, true);
+		assert(man);
+		my_manager_ = man;
+		(**man).add_event_handler(command_, true);
 	}
 
 	// Hotkey support
@@ -349,37 +355,39 @@ void wml_menu_item::update(const vconfig & vcfg)
  */
 void wml_menu_item::update_command(const config & new_command)
 {
-	// If there is an old command, remove it from the event handlers.
-	if ( !command_.empty() ) {
-		assert(resources::game_events);
-		manager::iteration iter(event_name_, *resources::game_events);
-		while ( handler_ptr hand = *iter ) {
-			if ( hand->is_menu_item() ) {
-				LOG_NG << "Removing command for " << event_name_ << ".\n";
-				resources::game_events->remove_event_handler(command_["id"].str());
+	if (boost::shared_ptr<manager * const> man = my_manager_.lock()) {
+		// If there is an old command, remove it from the event handlers.
+		if ( !command_.empty() ) {
+			manager::iteration iter(event_name_, **man);
+			while ( handler_ptr hand = *iter ) {
+				if ( hand->is_menu_item() ) {
+					LOG_NG << "Removing command for " << event_name_ << ".\n";
+					(**man).remove_event_handler(command_["id"].str());
+				}
+				++iter;
 			}
-			++iter;
 		}
-	}
 
-	// Update our stored command.
-	if ( new_command.empty() )
-		command_.clear();
-	else {
-		command_ = new_command;
+		// Update our stored command.
+		if ( new_command.empty() )
+			command_.clear();
+		else {
+			command_ = new_command;
 
-		// Set some fields required by event processing.
-		config::attribute_value & event_id = command_["id"];
-		if ( event_id.empty() && !item_id_.empty() ) {
-			event_id = item_id_;
+			// Set some fields required by event processing.
+			config::attribute_value & event_id = command_["id"];
+			if ( event_id.empty() && !item_id_.empty() ) {
+				event_id = item_id_;
+			}
+			command_["name"] = event_name_;
+			command_["first_time_only"] = false;
+
+			// Register the event.
+			LOG_NG << "Setting command for " << event_name_ << " to:\n" << command_;
+			(**man).add_event_handler(command_, true);
 		}
-		command_["name"] = event_name_;
-		command_["first_time_only"] = false;
-
-		// Register the event.
-		LOG_NG << "Setting command for " << event_name_ << " to:\n" << command_;
-		assert(resources::game_events);
-		resources::game_events->add_event_handler(command_, true);
+	} else {
+		ERR_NG << "Tried to set a command for a menu item, but the manager could not be found\n";
 	}
 }
 

src/game_events/menu_item.hpp

@@ -24,6 +24,9 @@
 #include "../tstring.hpp"
 #include "../variable.hpp"
 
+#include <boost/shared_ptr.hpp>
+#include <boost/weak_ptr.hpp>
+
 class filter_context;
 class game_data;
 struct map_location;
@@ -31,6 +34,7 @@ class unit_map;
 
 namespace game_events
 {
+class manager;
 
 class wml_menu_item
 {
@@ -57,7 +61,7 @@ public:
 	/// Removes the implicit event handler for an inlined [command].
 	void finish_handler() const;
 	/// Initializes the implicit event handler for an inlined [command].
-	void init_handler() const;
+	void init_handler(const boost::shared_ptr<manager * const> &) const;
 	/// The text to put in a menu for this item.
 	/// This will be either translated text or a hotkey identifier.
 	std::string menu_text() const
@@ -98,6 +102,9 @@ private: // Data
 	bool use_hotkey_;
 	/// If true, allow using the menu to trigger this item.
 	bool use_wml_menu_;
+
+	/// A link back to my manager
+	mutable boost::weak_ptr<manager * const> my_manager_;
 };
 
 } // end namespace game_events

src/game_events/wmi_container.cpp

@@ -133,7 +133,7 @@ std::vector<std::pair<boost::shared_ptr<const wml_menu_item>, std::string> > wmi
 /**
  * Initializes the implicit event handlers for inlined [command]s.
  */
-void wmi_container::init_handlers() const
+void wmi_container::init_handlers(const boost::shared_ptr<manager * const> & man) const
 {
 	// Applying default hotkeys here currently does not work because
 	// the hotkeys are reset by play_controler::init_managers() ->
@@ -149,7 +149,7 @@ void wmi_container::init_handlers() const
 	// Loop through each menu item.
 	BOOST_FOREACH( const item_ptr & wmi, *this ) {
 		// If this menu item has a [command], add a handler for it.
-		wmi->init_handler();
+		wmi->init_handler(man);
 		// Count the menu items (for the diagnostic message).
 		++wmi_count;
 	}

src/game_events/wmi_container.hpp

@@ -38,7 +38,7 @@ class vconfig;
 namespace game_events
 {
 class wml_menu_item;
-
+class manager;
 
 /// A container of wml_menu_item.
 class wmi_container{
@@ -85,7 +85,7 @@ public:
 		return get_items(hex, gamedata, fc, units, begin(), end());
 	}
 	/// Initializes the implicit event handlers for inlined [command]s.
-	void init_handlers() const;
+	void init_handlers(const boost::shared_ptr<manager * const> &) const;
 	void to_config(config& cfg) const;
 	/// Updates or creates (as appropriate) the menu item with the given @a id.
 	void set_item(const std::string& id, const vconfig& menu_item);